Evapotranspiration and its components over a rainfed spring maize cropland under plastic film on the Loess Plateau, China

• Gao, Xiang ^[2] ; Gu, Fengxue ^[3] ; Gong, Daozhi ^[3] ; Hao, Weiping ^[3] ; Chu, Jianmin ^[1] ; Li, Haoru ^[3]
  1. [1] Chinese Academy of Forestry

     Chinese Academy of Forestry

     China

     
  2. [2] Key Laboratory of Dryland Agriculture, Ministry of Agriculture and Rural Affairs of the People’s Republic of China, Beijing 100081 Key Laboratory of Tree Breeding and Cultivation of National Forestry and Grassland Administration, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091
  3. [3] Key Laboratory of Dryland Agriculture, Ministry of Agriculture and Rural Affairs of the People’s Republic of China, Beijing 100081

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• Localización: Spanish journal of agricultural research, ISSN-e 2171-9292, ISSN 1695-971X, Vol. 18, Nº. 4, 2020
• Idioma: inglés
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  • Aim of study: To determine seasonal variations in evapotranspiration (ET) and its components; and ascertain the key factors controlling ET and its components in a rainfed spring maize field under plastic film.Area of study: Shouyang County in Shanxi Province on the eastern Loess Plateau, ChinaMaterial and methods: Eddy covariance system combined with micro-lysimeters and meteorological observing instruments were used in the field. The manual method was used to measure the green leaf area index (GLAI) during the growing season.Main results: In 2015 and 2016, the growing season ET accounted for 80% and 79% of annual ET, respectively. Soil evaporation (E) accounted for 36% and 33% of the growing season ET in 2015 and 2016, respectively. The daily crop coefficient increased with increasing GLAI until a threshold of ~3 m2 m−2 in the canopy-increasing stage, and decreased linearly with decreasing GLAI in the canopy-decreasing stage. At equivalent GLAI, daily basal crop coefficient and soil water evaporation coefficient were generally higher in the canopy-increasing and -decreasing stages, respectively. During the growing season, the most important factor controlling daily ET, T, and E was net radiation (Rn), followed by GLAI for daily ET and T, and soil water content at 10-cm depth for daily E; during the non-growing season, daily ET was mainly controlled by Rn.Research highlights: The daily crop coefficient and its components reacted differently to GLAI in the canopy-increasing and -decreasing stages.